SCALING AND VORTEX DYNAMICS AFTER THE QUENCH OF A SYSTEM WITH A CONTINUOUS SYMMETRY

We study the dynamics of a system with a nonconserved complex order parameter, following a deep quench. In contrast to the case when the order parameter has a discrete symmetry, we observe an effective value of the dynamical exponent at early times of =0.375±0.005. In this regime, finite-size scaling of the scattering function is observed. At later times, we observe a crossover to =0.5±0.02. Our results indicate that any renormalization of the kinetic coefficient must be small. © 1990 The American Physical Society.